1. Field of the Invention
The present invention relates to an improved gas safety valve. In particular, the present invention relates to an improved gas safety valve that allows adjustment of a distance between a valve block and an inlet of a valve seat even though the elastic constant of a spring biasing the valve block is not within the predetermined operational range such that when excessive flow occurs, a longitudinal through-hole of the valve seat is reliably blocked by the valve block, thereby preventing mass leakage.
2. Description of the Related Art
Pressure difference has already been utilized in gas safety valves for assuring safety use of gas U.S. Pat. No. 5,983,928 to Hsiao issued on Nov. 16, 1999 discloses a gas safety valve comprising a valve body with a longitudinal through-hole for receiving a ball. The longitudinal through-hole of the valve body comprises several sections of various inner diameters such that when mass leakage occurs, the ball is moved to compress a spring and block the longitudinal through-hole as a result of a pressure difference between two sides of the ball. Such a structure can be applied to gas sources of different pressure by means of simply changing the spring. However, the elastic constant of springs cannot be always identical even if they are manufactured under the same condition and thus fail to meet the requirement of precision. Namely, the ball might be incapable of blocking the longitudinal through-hole of the valve body, as the elastic constant of the spring is not within the predetermined operational range.
It is the primary object of the present invention to provide an improved gas safety valve that allows adjustment to assure blockage of the longitudinal through-hole of the valve body, thereby preventing mass leakage.
The gas safety valve in accordance with the present invention allows adjustment of a distance between a valve block and an inlet of a valve seat by means of adjusting the position of an adjusting element that is mounted in the valve seat and has an end to which an end of a spring is attached. The other end of the spring is attached to the valve block. Thus, even though the elastic constant of the spring is not within the predetermined operational range, the distance between the valve seat and the valve block can be adjusted such that when excessive flow occurs, a longitudinal through-hole of the valve seat is reliably blocked by the valve block, thereby preventing mass leakage.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.